A software proposal for determining the prevailing wind direction: PrevailingWindRUB 1.0
Sedat AvcıKnowing the characteristics of the climatic elements of a place is of great importance in spatial studies. Although not used as often as temperature and precipitation, wind might be used as a guide especially in planning studies. Wind is mostly a horizontal movement. The direction, speed and the frequency of the wind are the three most prominent characteristics. Establishing the prevailing wind direction in terms of angle will provide more realistic results. Rubinstein states that the prevailing wind direction can be determined in degrees based on how often the wind blows from which direction. In the proposed method, the ratio of the directions from which the wind blows to all directions is used. While doing this, considering certain relations with the shares belonging to different directions at the same time makes this method more advantageous over others. In this method, data on calm days are not used. The method shows the second order prevailing wind direction and frequency, if available. The software attached to the article is proposed to determine the prevailing wind direction using the Rubinstein method.
Hâkim rüzgâr yönünün belirlenmesi için bir yazılım önerisi: PrevailingWindRUB 1.0
Sedat AvcıBir yerin iklim elemanlarına ait özelliklerin bilinmesi, mekânsal çalışmalarda büyük öneme sahiptir. İklim elemanlarından rüzgâr, sıcaklık ve yağış kadar sık kullanılmasa da özellikle planlama çalışmalarında yönlendirici olma özelliğine sahiptir. Genel atmosfer sirkülasyonuna bağlı olarak zemine yakın hava kütlelerinin yer değiştirmesi şeklinde tanımlanan rüzgâr, büyük ölçüde yatay yönde bir harekettir. Rüzgârın yönü, hızı (şiddeti) ve esiş sıklığı (frekansı) en belirgin üç özelliğini oluşturmaktadır. Hâkim rüzgâr yönünün belirlenmesi ve gösteriminde temel olarak rüzgârın hangi yönden kaç kez estiği esas alınmaktadır. Rüzgâr rasatları 8 veya 16 yöne göre ifade edilmektedir. Gerçekte ise hâkim rüzgâr yönü daha farklı olabilir. Hâkim rüzgâr yönünün açı cinsinde ortaya konulması, gerçeğe daha yakın sonuçları yansıtacaktır. Rubinstein, rüzgârın hangi yönden ne kadar sıklıkla estiğini esas alınarak hâkim rüzgâr yönü derece cinsinden belirlenebileceğini ifade etmektedir. Önerilen yöntemde, her yöne ait esme sayılarının toplam içindeki oranı kullanılmaktadır. Bu işlemi yaparken aynı zamanda farklı yönlere ait paylar ile de belli ilişkilerin göz önüne alınması, yöntemi diğer yöntemlere nazaran daha avantajlı hale getirmektedir. Yöntemde sakin günlere ait veriler ise kullanılmamaktadır. Ayrıca varsa ikinci dereceden hâkim rüzgâr yönünü ve frekansını da göstermesi Rubinstein metodunu öne çıkarmaktadır. Makale ekindeki yazılım Rubinstein yöntemiyle hâkim rüzgâr yönünün belirlenmesi için önerilmiştir.
Knowing the characteristics of the climatic elements is of great importance in spatial studies. Although it is not used as often temperature and precipitation, wind can be a guide especially in planning studies. Wind is defined as the displacement of air masses close to the ground depending on the general atmospheric circulation and it is mostly a horizontal movement. The direction, speed and frequency of the wind are the three most prominent characteristics. The main representation of prevailing wind direction is based on how many times the wind blows from a certain direction.
There are various methods for determining the prevailing wind direction. The easiest method is to draw a windmill based on the wind counts. However, wind observations are expressed according to 8 or 16 directions. However, in reality the prevailing wind direction may be different. Determining the prevailing wind direction in terms of angle will reflect more realistic results. Therefore, one of the various methods that have been developed is the geometric method.
The geometric method is based on the formation of a windmill and determining the resultant force of the two branches of the windmill in a clockwise direction starting from the north. In the method, the branches of the windmill must be formed according to a scale proportional to the number of blows. However, this method causes difficulties in showing the directions where the number of blows is very low and it is insufficient to reflect the truth. Therefore, it could not find much use. In determining the prevailing wind directions, the use of formulas is much more common. A formula developed by Lambert is not preferred because its use and the expression of the results are unclear. The formula developed by Rubinstein in determining the prevailing wind direction gives results that are more realistic.
The Rubinstein method is different from others because it it includes not only the direction of the most blowing wind but also other directions in the calculation and uses the ratio of these numbers in the total. It also highlights the Rubinstein method by showing the second-order wind direction, if any, and determining the percentages of the prevailing wind direction / directions. The most negative aspect of the method is that it is based on the blow number, not the blow time. In the Rubinstein method, long annual average values of the fly directions are used.
Basic of Rubinstein Method: This method is based on the blowing numbers of the wind. Rubinstein states that the number of blows in successive directions must have a certain pattern in order for the prevailing wind to form. For this purpose, first, the percentage of blow numbers belonging to each direction is found. Then, a sequence is created provided that the third term is greater than the first term and the second term is greater than the fourth term, and that the sum of the second and third terms is at least 25%.
The formation of a sequence indicates that there is only one prevailing wind direction. Formation of two sequences indicates there is a second-order wind direction. If no sequence is formed, it means that the prevailing wind direction does not appear. When a sequence is formed, the following formula is used to find the prevailing wind direction from the beginning of the sequence.
The multiplication of the number obtained by 45 shows how many degrees the prevailing wind direction is from the clockwise direction from the beginning of the sequence. The frequency of the prevailing wind direction is;
The program performs these calculations and prints direct results.
Use of PrevailingWindRUB 1.0 software:
Wind data is prepared according to international standards in 16 directions. In the DATA tab, enter the number of blows for each direction in the relevant cells in the table. Rubinstein method calculates according to 8 directions. If your data set belongs to 8 directions, you need to use the table where you can enter values for 8 directions in the relevant part of the same tab. In the RESULT tab, if monthly data is entered, the prevailing monthly, seasonal and annual wind direction is expressed in terms of frequency and angle in percentage. If daily or other period data is entered, there are values for the prevailing wind direction in the row with the entered data.
